Speakers are well-known in the prior art for providing the user with listening enjoyment of music. In particular, high-performance speakers cooperate with stereo systems to provide extreme clarity of various bass, mid-range and treble music components of the audible frequency spectrum. To do this, a high-performance speaker typically incorporates a woofer component, mid-range component and a tweeter component to provide the respective low frequency, mid-range frequency and high frequency components of a sound pattern.
Most high performance stereo systems also include a center channel loudspeaker. Ideally, a center channel loudspeaker has good measurable sonic performance even when the listener is off-axis. Stated differently, an ideal speaker has a uniform output of low frequency, mid-range frequency and high frequency components of the sound pattern for extreme clarity, even when the listener is not positioned directly in front of the center channel speaker.
In a typical prior art speaker, the tweeter and the mid-range components are oriented one above the other so that their respective sound patterns emanate from the center of the loudspeaker face. Alternatively, the tweeter and mid-range components are co-axially oriented so that the center axis of their sound patterns are coincident. In either case, there are typically at least two woofers that are symmetrically arranged around the tweeter and the mid-range component. Further, for all arrangements, the tweeter, mid-range component and woofers are all positioned so that they emit their respective patterns directly outward from the speaker.
When a speaker has one of the above component arrangements, the frequency response of the speaker becomes degraded if the listener is off-axis because the center axes of the low frequency, mid-range frequency and high frequency sound patterns are not coincident. Specifically, the listener tends to get an increased concentration of low frequency response because the listener is no longer positioned symmetrically between the woofer outputs, and the overall signal that is received by the listener becomes distorted by the low-frequency component of the sound pattern.
One solution to the asymmetrical frequency performance is to arrange the woofer and the tweeter co-axially, so that the respective center axes of the low-frequency and high-frequency sound beams are coincident. In this arrangement, however, the woofer becomes limited in power-handling capabilities. To address the power handling problem, another woofer is typically added, but this can sometimes become impractical, particularly when a small-size speaker is desired. What is needed is a speaker wherein the woofers are arranged in such a manner that the center axis of the emitted low-frequency beam is coincident with the center axes of the mid- and high-frequency sound beams emanating from the respective mid-range and tweeter components. If this is achieved, a uniform intensity of sound is heard by the listener over the entire audible spectrum, even if the listener is not centered directly in front of the speaker.
In light of the above, it is an object of the present invention to provide a speaker wherein a uniform response is received by the listener over the entire audible frequency range, even if the listener is not located directly in front of the speaker. It is another object of the present invention to provide a speaker wherein the emanating sound patterns of the woofer are superimposed over the sound patterns of the tweeter and mid-range components, to form a single tri-axial sound pattern from the speaker. Yet another object of the present invention is to provide a speaker wherein the center axis of the emitted low frequency beam is coincident with the center axes of the emitted mid-range frequency and high frequency sound beams. It is another object of the present invention to provide a speaker wherein a low frequency sound duct is arranged and symmetrically oriented around the tweeter and the mid-range components of the speaker. Another object of the present invention is to provide a speaker with a wider listening area which achieves lower distortion and higher power handling capabilities along with a flat global frequency response. Yet another object of the present invention is to design a speaker which is easy to use and is cost effective to manufacture.